A dental implant can be surgically implanted in a dental patient and a prosthesis mounted on the implant to replace a natural tooth that the patient has lost due to decay or injury. Such a dental prosthesis can be an artificial tooth or crown that affixes to a post that is secured to the patient's alveolar ridge, the bone ridge that forms the borders of the upper and lower jaws and contains the sockets of the patient's teeth.
Some of the problems with prior art dental implant fixtures are explained with reference to FIG. 1. A patient's jawbone 10 includes a neurovascular bundle 12 or a sinus that limits the depth at which a dental implant fixture 14 can be positioned into the jawbone thereby limiting the anchor strength of the dental implant fixture. Another frequently observed problem related to the implantation of a dental prosthesis is that when a prosthesis is needed by a patient, it usually is needed where the patient has also experienced bone loss or deterioration in the alveolar ridge. When, as a result of disease or injury, bone loss has occurred in or around where a dental prosthesis is needed, it may be that there is not enough bone in which to implant a dental implant fixture in the alveolar ridge. As a result, the anchor strength of the dental implant fixture 14 will be diminished because the dental implant fixture 14 will need to be smaller in size to compensate for the narrow ridge width. Conventional devices and methods have sought to address these problems through different types of dental implant fixtures with each requiring a succession of surgical procedures.
For example, U.S. Pat. No. 5,324,199 to Branemark discloses a dental fixture anchored below the neurovascular bundle in the basal bone. The dental fixture includes a cylindrical shaft having opposing threaded ends and a thread-free midsection. The dental fixture is inserted into a prepared hole in the jawbone with the nerve being lifted out of the way. After the dental fixture is positioned, the nerve is repositioned against the thread-free midsection. At a later date when the dental fixture becomes integrated into the jawbone, the dental prosthesis can be fitted on the dental fixture.
Similarly, U.S. Pat. Nos. 5,725,376 and 6,814,575 and U.S. Published Application 2005/0037320 to Poirier disclose a computer system for modeling a patient's teeth and jawbone. The model is used to produce a drill guide to aid the surgeon in preparing the implant hole for a dental fixture in the patient's jawbone that avoids the neurovascular bundle. The model is also used to produce the dental fixture inserted into the implant hole. A dental prosthesis is attached to the dental fixture at a date after the dental fixture is implanted into the patient's jawbone.
U.S. Pat. No. 6,319,006 to Scherer et al. discloses modeling a patient's jawbone using an x-ray image superimposed on a three dimensional image to map out an implant hole for a dental fixture. The map is used to locate the nerve thereby setting a lower limit for the implant hole and to produce a drill guide used to create the implant hole.
Unfortunately, such conventional techniques and dental fixtures require a patient to make multiple visits to the attending physician and/or may require a lengthy interval between the initial operation and the final installation of the dental prosthesis.